Printing systems may use liquid inks which are stored in ink tanks. These liquid inks are pumped from the ink tanks through the printing system during the printing process. In some cases it may be desirable to change the color or type of inks used by the printing system. For example, a new print run may require the replacement of a particular ink with a specialized spot color ink to achieve a desired metallic, fluorescent, or tint effect. Ideally, the entire printing system would be cleaned to remove residuals of the first ink to avoid cross contamination of the replacement ink. The process of changing inks may be a manual and lengthy process which requires the operator to remove the ink tank, drain the current ink from the ink tank, clean the ink tank, purge the supply lines and printing apparatus to remove residuals of the first ink from the system, and then refill the ink tank with the replacement ink. To facilitate the flexibility and ease of changing inks within a printing system, it is desirable to automate the ink color change process.
Additionally, it may be desirable to periodically clean the printing system even if the colors of the ink remain the same. These maintenance cleanings can improve the printing performance of the system, extend the lifetime of various components, and improve the efficiency of the printing system. Manual maintenance cleanings can take a significant amount of time and training to perform. During this time period, the printing system is typically idle. By automating these maintenance cleanings, the cleanings could be performed more quickly, accurately, and with less training.
Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements.